/*
 * null_auth.c
 *
 * implements the do-nothing auth algorithm
 *
 * David A. McGrew
 * Cisco Systems, Inc.
 *
 */

/*
 *
 * Copyright (c) 2001-2006, Cisco Systems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 *   Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 *   Neither the name of the Cisco Systems, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "null_auth.h"
#include "alloc.h"
#define LOG_TAG "Srtp-1.4.4"

/* null_auth uses the auth debug module */

extern debug_module_t mod_auth;

err_status_t null_auth_alloc(auth_t **a, int key_len, int out_len) {
    extern auth_type_t null_auth;
    uint8_t *pointer;

    debug_print(mod_auth, "allocating auth func with key length %d", key_len);
    debug_print(mod_auth, "                          tag length %d", out_len);

    /* allocate memory for auth and null_auth_ctx_t structures */
    pointer = (uint8_t*) crypto_alloc(sizeof(null_auth_ctx_t) + sizeof(auth_t));
    if (pointer == NULL)
        return err_status_alloc_fail;

    /* set pointers */
    *a = (auth_t *) pointer;
    (*a)->type = &null_auth;
    (*a)->state = pointer + sizeof(auth_t);
    (*a)->out_len = out_len;
    (*a)->prefix_len = out_len;
    (*a)->key_len = key_len;

    /* increment global count of all null_auth uses */
    null_auth.ref_count++;

    return err_status_ok;
}

err_status_t null_auth_dealloc(auth_t *a) {
    extern auth_type_t null_auth;

    /* zeroize entire state*/
    octet_string_set_to_zero((uint8_t *) a, sizeof(null_auth_ctx_t)
            + sizeof(auth_t));

    /* free memory */
    crypto_free(a);

    /* decrement global count of all null_auth uses */
    null_auth.ref_count--;

    return err_status_ok;
}

err_status_t null_auth_init(null_auth_ctx_t *state, const uint8_t *key,
        int key_len) {

    /* accept any length of key, and do nothing */

    return err_status_ok;
}

err_status_t null_auth_compute(null_auth_ctx_t *state, uint8_t *message,
        int msg_octets, int tag_len, uint8_t *result) {

    return err_status_ok;
}

err_status_t null_auth_update(null_auth_ctx_t *state, uint8_t *message,
        int msg_octets) {

    return err_status_ok;
}

err_status_t null_auth_start(null_auth_ctx_t *state) {
    return err_status_ok;
}

/*
 * auth_type_t - defines description, test case, and null_auth
 * metaobject
 */

/* begin test case 0 */

auth_test_case_t null_auth_test_case_0 = { 0, /* octets in key            */
NULL, /* key                      */
0, /* octets in data           */
NULL, /* data                     */
0, /* octets in tag            */
NULL, /* tag                      */
NULL /* pointer to next testcase */
};

/* end test case 0 */

char null_auth_description[] = "null authentication function";

auth_type_t null_auth = { (auth_alloc_func) null_auth_alloc,
        (auth_dealloc_func) null_auth_dealloc, (auth_init_func) null_auth_init,
        (auth_compute_func) null_auth_compute,
        (auth_update_func) null_auth_update, (auth_start_func) null_auth_start,
        (char *) null_auth_description, (int) 0, /* instance count */
        (auth_test_case_t *) &null_auth_test_case_0 };

